The invention relates to a milling machine, in particular to a road milling machine, a stabiliser, a recycler or a surface miner, having a drive means which is configured such that the milling machine performs translatory and/or rotatory movements on the ground, and a working means which is configured such that the ground is machined. The invention also relates to a method for operating a milling machine of this type.
Different embodiments of ground milling machines are known, which include in particular road milling machines, stabilisers, recyclers or surface miners. The known milling machines are distinguished by a drive means for carrying out translatory and/or rotatory movements of the machine on the ground and by a working means for machining the ground. The drive means has at least one assembly which performs a specific machine function subject to drive parameters, and the working means has at least one assembly which performs a specific machine function subject to work parameters. In turn, the individual assemblies of the drive means and of the working means can comprise a plurality of components.
In the following, “a drive means” is understood as meaning all the components of the road milling machine which are intended or are suitable for moving the machine, and “a working means” is understood as meaning all the components of the road milling machine which are intended for or are suitable to be used during the machining of the ground. The drive means and the working means can also have common components. A common component of the drive means and of the working means can be a driving engine, in particular an internal combustion engine.
The driving power of the internal combustion engine can be transmitted to hydraulic pumps by a pump distributor gearbox to supply hydraulic motors, provided in the running gear units of the milling machine, with hydraulic fluid. The drive means then comprises the internal combustion engine, the pump distributor gearbox, the hydraulic pumps and the running gear units with the hydraulic motors. The travel speed of the milling machine can be controlled continuously by a corresponding adjustment of the hydraulic pumps at different speeds of the internal combustion engine.
A fundamental assembly of the working means is the milling/cutting drum which, in the case of known milling machines, is arranged in a milling drum housing. The milling/cutting drum is generally driven by the single driving engine of the milling machine, the driving power of the driving engine being transmitted to the milling/cutting drum by a mechanical transmission. Thus, the speed of the milling/cutting drum is determined by the speed of the internal combustion engine and by the transmission ratio of the transmission. The milling/cutting drum can also be driven hydraulically, for example, in which case the speed is controlled via a corresponding adjustment of the hydraulic pumps.
However, the working means can also comprise further assemblies which cooperate with the milling/cutting drum to machine the ground. Included here are, for example, a hold-down device which can be adjusted in height relative to the ground and which is arranged upstream of the milling/cutting drum in the working direction of the milling machine, or a stripping device which can be adjusted in height relative to the ground, which rests on the ground with a predetermined contact force and is arranged downstream of the cutting/milling drum in the working direction of the milling machine, or an edge protection device which can be adjusted in height relative to the ground, which rests on the ground with a predetermined contact force and is arranged in the longitudinal direction of the milling machine.
Milling machines have a central control and processing unit which is configured such that the assemblies of the drive means are controlled such that a specific machine function is carried out, and the assemblies of the working means are controlled such that a specific machine function is carried out. A specific machine function is carried out subject to specific operating parameters which are preset by the machine operator. In the following, the operating parameters which are considered during the control of the assemblies of the drive means are denoted as drive parameters and the parameters which are considered during the control of the assemblies of the working means are denoted as work parameters.
In order to input the drive and work parameters, milling machines have a control unit which can be configured in different ways. The control unit can have, for example, pushbuttons or switches, sliders or joysticks, or it can be configured as a touch screen.
The operation of a milling machine is a complex task for the machine operator. The machine operator must preset all the drive and work parameters so that the desired milling result is achieved. In this respect, the machine operator must bear in mind that presetting one operating parameter can directly influence another parameter. During operation of the milling machine, the interaction of all the parameters is critical for the quality of the milled surface. Therefore, the operation of a milling machine requires a very experienced machine operator.